At the picture I am in the additive storage holding iron ore in my hand, the black material. The next pile is sand and the last one is chalk.
This is marl in the marl storage. The machine on the picture is a reclaimer.
Here I am holding gypsum from the pile with gypsum.
Marl, gypsum, chalk and sand come from the same quarry.
On the picture I am standing in front of one of the big excavortors in the guarry.
Samples are taken either manually or automatically, and are taken from three locations:
• Raw Meal Silo (CF Silo)
• Clinker cooler / Crusher
• Air slide to cement silo
From the CF Silo samples of circa170 g are taken spot-wise with an interval of 10 minutes. After one hour all samples are brought [...]to the lab.
From the Clinker cooler / crusher and the air slide to the cement silos samples of circa 1 kg are taken every hour, so that a total of 24 samples are taken every day.
The “hour samples” are tested individually, and once a day a portion of every “hour sample” is taken and mixed together into a “day sample”, which is also being tested.
The material is transported from the Drier Crusher to the CF Silo. From the CF Silo samples are taken.
In the lab, the samples are homogenised in the Sample Splitter.
On the picture you see raw meal and the sample splitter is the grey one behind me. Read more...↑
Then, samples portions of powder are tested for residue (for fineness) by determining the average particle size. The powder sample is placed in a sieving machine (picture). The aim is to produce cement with an average particle size of 90 µm.
Another portion is tested for moisture content in accordance with FLS standard 110. The test is done by weighing the sample, then heating it in an oven at 110 °C for 60 minutes, and then weighing it again. The aim is a max. content of 0.7 % moisture.
A third portion is analysed in [...]the X-ray machine (picture) for chemical composition.
From the Clinker Crusher the material is transported to the Cement Mills and from there to the Cement Silos. Samples are taken from the air slide, right before it gets to the Cement Silos.
In the lab, a portion of the cement sample is tested for surface density. The [...]sample is poured in the Blaine air permeability test apparatus (picture) and pressed lightly with a thumb into a well-defined bed; a reference standard is made for the thumb pressure of every chemist. Then, air is pumped into the Blaine apparatus building up a pressure. When the pressure drops, air is drawn through the bed, the time it takes for the fluid to drop between two marks is registered, and the surface density is computed by use of Excel. The target is 3200 cm2/g.
Another portion is tested for the setting time in the machine you see on the picture. A diluted cement sample is poured in a beaker, which solidifies for approximately 30–35 minutes. Thereafter a steel needle is plunged into the sample to see, if the sample is set. This test is [...]done either manually or automatically. Read more...↑
A third portion is prepared for strength testing. The cement is stirred together with EN-standardised sand and water in a mortar mixer (picture).
After mixing, the specimen is compacted to a 40×40×160 mm prism in a jolting table (60 bumps/minute). After 24 hours humid storing, de-forming and 28 days wet storing in a water tank, the cement specimen is ready for compression test.
Compression test is carried out in accordance with EN 196 by placing the [...]prism in a compression and bend test plant (picture) and loading up to failure; target strength in the range of 50 MPa. It’s also possible to carry out a 3-point flexural strength test.